The present invention relates to the detection of aircraft descent anomaly.
Collision risk warning systems in the event of an aircraft approaching the ground dangerously exist.
For example, the following systems are known:                TAWS (Terrain Awareness and Warning System),        EGPWS (Enhanced Ground Proximity Warning System) or also        GCAS (Ground Collision Avoidance System).        
These systems generate warnings (audible and/or visual) intended for the crew of the aircraft, on the basis of collision warning algorithms that can be “reactive” or “predictive”.